The phrase “cervical insufficiency” (CI) refers to a cervix that opens too early, before the baby is full term. This condition is also called incompetent cervix. The cervix is the opening at the base of the uterus.

When the cervix is healthy, it thins out and opens at the end of pregnancy when labor begins. The baby then moves through the cervix and birth canal (vagina) to be delivered.

With CI, the cervix opens without labor starting. Usually the woman has no symptoms. Few women know they have cervical insufficiency until they have a miscarriage or premature birth. The woman may deliver the baby without feeling contractions.

For women who have had a pregnancy affected by CI, the condition is likely to happen again in later pregnancies.

Causes
Medical experts do not always know why incompetent cervix occurs. Theories include damage to the cervix during surgery, injury during a previous birth, and exposure to certain drugs.

Cervical length appears to be a factor. The shorter the cervix, the more likely the woman is to have cervical insufficiency. 

Screening and Diagnosis
Medical researchers have not found a reliable way to routinely screen women for cervical insufficiency. If a woman has previously lost a pregnancy in the second or third trimester, vaginal ultrasound exams during the next pregnancy may help predict whether a woman is at risk of preterm birth. 

Treatment
Doctors sometimes recommend:

• Bed rest and reduced physical activity. While these methods are common, medical research has not proven them to be effective.
• Pelvic rest. The woman should not douche or use tampons. She also should not have sexual intercourse.
• Cerclage. The doctor puts a stitch in the cervix to keep it from opening too early. The stitch is removed when it is time for the baby to be delivered.

Where Can I Talk to Other Women About Cerclage?
Join the discussion group about cerclage on the March of Dimes online community Share Your Story.

July 2009